This invention relates to devices for retaining the top peripheral edge portion of a watertight liner such as the type used in the construction of swimming pools.
A common and well known method of constructing swimming pools comprises the erection or placement of fixed walls and a floor for the pool which are not watertight but which have sufficient structural strength to contain the water. A pool liner is required in such a pool to make it watertight. The liner is constructed from a waterproof sheet material which often made is from vinyl. The liner has a top peripheral edge portion that corresponds with or is located adjacent to the top of the structural walls of the pool. Various methods have been proposed and used to attach the top peripheral edge of the liner to the top of the pool walls in order to ensure that the liner does not slip down below the water line. Many of these methods involve the use of preformed coping members which finish and round the top peripheral edge of the pool for safety and attractive appearance. Commonly, a groove or slot is provided in this coping for receiving a thickened liner bead formed on the top peripheral edge portion of the liner. A longitudinal flange located adjacent to the mouth of the slot engages a corresponding flange or lip in the liner bead in order to retain the liner edge. One difficulty with such a method arises from the fact that in order to insert the liner bead into the slot, the bead and slot must be dimensioned loosely. This fact can result in the liner being pulled out of the coping slot. If this should occur, the liner normally cannot be reinserted into the coping without draining the pool.
In U.S. Pat. No. 4,158,244 issued Jun. 19, 1979 to Timerax Holdings Ltd. a coping or retaining element, in addition to having a holding channel for accommodating the liner bead, has a generally cylindrical hinge channel communicating with the holding channel. An elongate resilient U-shaped insert is located in the hinge channel. This insert has an outward closing element depending from the hinge channel to partially close a longitudinal outward slot defined by the two channels. A rib arrangement is provided to prevent rotation of the insert in the hinge channel. The closing element is biased towards the slot so that, after insertion of the liner bead, the insert engages a stop, partially closes the slot, and retains the liner bead. While this retainer works well, it requires the insert to be installed inside the retaining element, which is inconvenient.
U.S. Pat. No. 4,713,849 issued Dec. 22, 1987 discloses a retaining element defining a holding channel adapted to accommodate the bead of the pool liner. The channel defines an outwardly disposed longitudinal slot for insertion of the bead into the channel. The retaining element includes a downwardly extending flange forming an upper edge of the slot. An elongate clip has a longitudinal cavity extending there along adapted to receive the flange, the clip partially closing the slot. After the bead has been inserted into the slot, the clip can be mounted on the flange to partially close the slot and retain the liner bead. While this retainer also works very well, a difficulty with it is that once the bead has been inserted into the slot and the clip mounted on the flange, the bead cannot be removed from the slot without removing the clip. Removal of the clip tends to cause damage either to the clip or the retaining element.
The present invention provides a retainer structure which is easy to install yet capable of retaining the top peripheral edge portion or bead of a pool liner while allowing the liner bead to be easily removed from such retainer, if desired.
According to one aspect of the present invention, there is provided a retainer for accommodating a pool liner having a bead with a height greater than its width and an offset lateral edge portion. The retainer comprises an elongate retaining element including means defining a longitudinal holding channel for accommodating the pool liner bead. The holding channel has an upper wall, a rear wall and a bottom wall. The bottom wall has a forwardly positioned, upwardly extending first flange and the upper wall has a downwardly extending second flange. The second flange extends from the upper wall toward the bottom wall and the area between the bottom of the second flange and the top of the first flange forms a slot for insertion of the liner bead into the holding channel. The upper wall also has a remotely extending third flange positioned outside of the channel. An elongate resilient cap defining a longitudinal cavity therein is also provided. The cap has a first hooked peripheral edge portion adapted to be hooked over the second flange, and an opposed second hooked peripheral edge portion adapted to be hooked over the third flange. The cap is retained on the retainer by snapping the hooked peripheral edge portions over the respective second and third flanges. The first peripheral edge portion has a transverse, outwardly disposed shoulder. When the cap is retained on the retainer, the cap shoulder extends toward the first flange but is spaced from the first flange a distance sufficient to allow the width of the liner bead to pass therethrough but not sufficient to allow the height of the liner bead to pass therethrough. The liner bead can be inserted into the retaining element with the liner bead lateral edge portion inside the first flange so that downward forces acting on said pool liner will cause the liner bead lateral edge portion to hook onto said first flange and swing into engagement with the cap shoulder, the cap shoulder thereby preventing separation of said liner bead from said holding channel.
According to another aspect of the invention, there is provided a swimming pool liner and retainer assembly comprising, in combination, a pool liner including a waterproof sheet having a top peripheral edge portion including a liner bead, the liner bead having a height greater than its width and an offset lateral edge portion, and a retainer as described next above, the liner bead being held in the retaining element by the cap.